At the group or category level you can add ?qna=answered or ?qna=unanswered or ?qna=question to the url of a category or group it will sort the questions accordingly so that only that type of content will display for example:
?qna=answered - will only show questions that have been marked with best answer
?qna=unanswered - will only show questions that have received a comment
?qna=question - will only show questions that don't have comments
The question I have is, is there a way to do the same with discussions? How can I, through the url, display only the discussions inside a category or group and also, how can I filter the discussions so that only discussions without comments appear?